In any user's Beatmaps page, it lists Ranked and Unranked. Thanks to the imposed quota, it would be really nice to differentiate between unranked and Graveyarded beatmaps. (Also, when it's implemented, Awesome-unrankable maps)
While functional, an icon would probably look out of place? Additionally, it's easier just to count the list of unranked maps when the graveyarded maps have their own category.